Your Right to Know

A man in Wisconsin viewed it as a technical challenge. Another, in New Hampshire, was looking to
save some money. And in Texas, a third wanted to make a political point.

The three might have had different motivations but their results were the same: Each built a
working gun that included a part made in plastic with a 3-D printer.

What they did was legal and, except for the technology and material used, not much different
from what do-it-yourself gunsmiths have been doing for decades. But in the wake of the shootings in
Newtown, Conn., and the intensified debate over gun control, their efforts, have stoked concerns
that the inexpensive and increasingly popular printers and other digital-fabrication tools might
make access to weapons even easier.

“We now have 3-D printers that can manufacture firearms components in the basement,” said Rep.
Steve Israel, D-N.Y. “It’s just a matter of time before a 3-D printer will produce a weapon capable
of firing bullets.”

A 3-D printer builds an object layer by layer in three dimensions, usually in plastic. There are
major technical obstacles to creating an entire gun on a 3-D printer, not the least of which is
that a plastic gun probably would melt or explode upon firing a single bullet.

However, Michael Guslick in Milwaukee, Chapman Baetzel in Dover, N.H., and Cody Wilson in
Austin, Texas, did something much simpler and, for now, more effective. They printed the part of an
AR-15 assault rifle called the lower receiver, the central piece that other parts are attached to.
Then, using standard metal components, including the chamber and barrel — the parts that must be
strong enough to withstand the intense pressure of a bullet firing — they assembled working
guns.

In all, the three men, who have written about their efforts on the Web, have fired hundreds of
rounds.

A lower receiver is the only part of an AR-15 that, when bought, requires the filing of federal
paperwork. But it is legal to make an AR-15 — and many other guns — for personal use as long as
there is no intent to sell it. And if the lower receiver is homemade, no paperwork is required.